Borehole tool

ABSTRACT

The particular embodiment described herein as illustrative of one form of the invention utilizes a motion-sensing device to control the operation of a timing circuit in a downhole borehole tool. The absence of motion for a predetermined period is indicative of the tool being at its operating position and permits an electronic counting circuit to initiate signals for operating the tool. Once the tool has operated, the circuit incorporates means for preventing further operation of the tool until the circuit is reset at the surface.

nited States Patent Lindsey [4 1 Jan. 25, 1972 [54] BOREHOLE TOOLPrimary Examiner-loseph W. Hartary AttorneyGeorge L. Church, Donald R.Johnson, Wilmer E. [72] lnventor: James M. Lmdsey, Houston, Tex.Mccorquodaie Jr and John Home. [73] Assignee: Sperry Sun Well SurveyingCompany,

Sugar Land, Tex. ABSTRACT 2 Apr 2 970 The particular embodimentdescribed herein as illustrative of one form of the invention utilizes amotion-sensing device to l Pl N04 25,003 control the operation of atiming circuit in a downhole borehole tool. The absence of motion for apredetermined [52] U 5 Cl 346/107, 33/205 5 P 307/] 16 period isindicative of the tool being at its operating position [51] 47/022 andpermits an electronic counting circuit to initiate signals [58] Fieid 5P 2055 for operating the tool. Once the tool has operated, the circuit95/11 5 307/116 incorporates means for preventing further operation ofthe Y tool until the circuit is reset at the surface. [56] ReferencesCited 7 Claims, 3 Draliag I UNITED STATES PATENTS 3,546,478 12/1970Lindsey ..307/116 46 RI PPLE COUNTER i 47 TIME BASE 48 49 JUUUL 44 I R Es ET mg TRIGGER AMPL F H l IER M OT 0 N DETECTOR 552%, A M P Ll Fl E RMOT I ON C'LAMP 4l\. DETECTOR TRIGGER L'AMP PATENIEB m2 5 I972 POWERSUPPLY ELECTRICAL CIRCUIT 4 RIPPLE COUNTER 6 47 TIME BASE JLIULIL fRESET LAMP TRIGGER DRIVE ll AMPLIFIER MOTION DETECTOR SE25 AMPLIFIERMOTION CLAMP 4| J DETECTOR TRIGGER I 52 la LAMP FIG. 2

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INVENTOR JAMES M. LINDSEY ATTORNEY BOREHOLE TOOL BACKGROUND OF THEINVENTION The present invention pertains to a borehole tool and moreparticularly to a device for initiating the operation of such a toolupon its being maintained in a motionless condition for a predeterminedtime period in the borehole.

When drilling boreholes in the ground, particularly boreholes which runpartly through rock and partly through looser earth layers, it oftenhappens that the dip or inclination of the hole to the horizontal planeas well as the direction of the hole will vary quite considerably atdifferent depths of the hole. In many cases, therefore, it is importantto determine the existing deviations from a desired inclination anddirection.

One such apparatus which has been used for the purposes outlined aboveis termed a single-shot magnetic directional survey instrument. Such aninstrument is used to obtain a single record of the inclination and thedirection of inclination at various depths in a borehole. The instrumentis used for the purpose of orienting a hole in directional drillingoperations, and also to chart the course of boreholes from surface tototal depth during a normal drilling operation. The directional featuresof the instrument consist of a magnetic compass. The inclination unit isa form of inverted plui'nb lbob. These two features are combined into asingle compass angle unit which may be available in various ranges ofdegrees of inclination. A camera unit in the instrument makes apermanent record of the compass angle unit reading at a preset moment intime. Electrical power to operate lamps in the camera unit may befurnished by batteries or by a conductor cable suspending the instrumentfrom the earth's surface. An electrical circuit for activating the lampsis controlled by a clock which allows a predetermined exposure period ofa film disc for recording the inclination .and direction of inclinationindicated by the compass angle unit. An adjustment feature on the clockallows the clock to be set for delayed times ranging from a few secondsto several hours.

In operating such an apparatus, a desired compass angle unit is selectedand assembled, and the batteries and film are loaded with the clockbeing set for the delayed time needed to reach the survey depth. Theinstrument is then assembled into a protective casing which can belowered and positioned in a nonmagnetic drill collar at the lower end ofthe drill stem with the apparatus being suspended on a wire line.Alternatively, the apparatus may be go-deviled into a nonmagnetic drill.collar and retrieved with an overshot or by pulling the drill string.The instrument may also be lowered into an open hole on a wire line, orby any other convenient method. The compass angle unit is normallycomprised of a floating magnetic needle designed so that its directionaland angular position may be simultaneously photographed on a disc.

Clock-operated survey instruments may be assembled and programmed justprior to the survey, since the clock must be set just before theinstrument is placed in the well. This is due to the many contingentfeatures that may occur in the drilling of a well which might delay thesurveying of the well.

In order to set an appropriate delay time in the timing mechanism of theinstrument, an estimation must be made as to the time it will take theinstrument tobe assembled and then either lowered into the wellbore on awire line or go deviled to the bottom. In any event, since the timelapse cannot be predicted with precise certainty, a liberal safetyfactor must be employed to insure that sufficient time will elapse topennit the instrument to he landed at the bottom of the borehole or atsurvey depth. In addition, timelmust be perveys are run in the course ofa day to determine the'orientation of the hole, the rig time expendedmay become critical, particularly in situations such as offshoreoperations where rig costs are extremely high. 1

Electronic circuitry which may be employed to operate such an apparatusmust be reliable and simple, not only to keep equipment costs low, butto provide for low maintenance and repair costs. The simplicity of suchcircuitry may be an important factor in reducing the size of theborehole tool, a factor that is always important in the design of suchtools.

It is therefore an object of the present invention to provide a new andsimplified device for operating downhole borehole tools.

SUMMARY OF THE INVENTION With this and other objects in view, thepresent invention contemplates an apparatus for initiating the operationof a downhole borehole tool, and includes a motion-sensitive devicewhich detects the presence of motion as the tool is being assembled andmoved into an operating position in the borehole. The motion-detectingdevice prevents the operation of the tool as long as the tool is inmotion. Upon cessation of such motion, a solid-state timing device isactivated, which in turn causes an electrical signal to be sent toportions of the tool to be operated by such electrical signals. After alapse of a predetermined period of time, the electrical signal foroperating the tool is interrupted, and a cutoff signal is applied to thetiming device to deactivate such timing device. Thus the tool will onlybe operated one time.

A complete understanding of this invention may be had by reference tothe following detailed description, when considered in conjunction withthe accompanying drawings illustrating embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of aninstrument for utilizing principles of the present invention;

FIG. 2 is a schematic diagram of an electrical circuit embodyingprinciples of the present invention; and

FIG. 3 shows a motion-detecting device for use with the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 ofthe drawings, a schematic view of a borehole surveying instrumentincludes at the upper end of the instrument a power supply section 11which may be in the form of a battery pack or a power supply circuitreceiving its power from a conductor cable (not shown) extending to thesurface. Immediately below the power supply housing is a control circuithousing 12 which contains the electrical circuitry for operating thesurveying apparatus. The lower section 13 of the. tool houses the surveyinstrument and includes a slot 14 for receiving a film disc 16 forrecording the survey. Below the film disc is a lens 17 with lamps 18being positioned below the lens. A glass disc 19 which contains areticle in its center is positioned below the lamps in the housing. Theglass disc also forms the upper end of a chamber 21 containing a fluidin which a compass angle unit 22 is pivotally floated. Indicia on thehead 20 of the compass angle unit provides a visual indication of thedirection and inclination of the tool housing. The buoyancy of the fluidin the chamber maintains the compass angle unit in a vertical positionon its pivot 23 throughout various positionings of the instrumenthousing in the borehole.

In the operation of the instrument described above, the electricalcircuit is activated at some instant of time to energize the lamps 18.The light emanating therefrom is directed through the glass disc 19 ontothe head 20 of the compass angle unit 22. The compass angle unitincludes a magnetic needle which is oriented in a north-south direction.In addition, the unit is permitted to tilt on its pivot 23 away from thelongitudinal axis of the tool, to provide an indication of theinclination of the tool in the wellbore. Light impinging upon the head20 of the'unit is reflected back through the glass enclosure 19 and the'reticle thereon, through the lens 17, and on to the film disc 16.Therefore, while the lamps are lighted, the film disc is exposed to theimage presented by the compass angle unit head and the reticle engravedon the glass. The record of this image provides an indication of thedirection and inclination of the borehole.

The present invention pertains to an improved device for initiating andtiming the operation of an instrument such as a directional surveyinginstrument. However, it is pointed out that the timing circuit wouldhave application to other types of borehole tools.

The apparatus of the present invention incorporates in an electricalcircuit, a motion-sensing device such as the ones shown in FIG. 3 of thedrawings. The apparatus of FIG. 3 includes a conductive housing 26. Thehousing is open at one end for receiving a plug 27 made of a conductivematerial. The plug is separated from the housing by an insulator 28 toprovide a pair of electrically insulated conducting surfaces. The plug27 has an upwardly extending portion 29 which is also insulated from thehousing, and which has a pivot point 31 at its upper end. The spacebetween the upper end of the upwardly extending portion 29 and the topof the housing 26 forms a chamber 32 which is sized to receive a ball33. The ball is constructed of chrome or other such electricallyconducting material. The inside wall surfaces 34 of the housing 26 whichsurround the chamber 32 are preferably roughened or threaded to providea multiplicity of contacting points thereon which renders the devicemore sensitive to motion thereof. The ball is received within thechamber 32 and in a motionless condition, the ball will rest on thepivot point 31 and against the inside roughened surfaces of the wall 34of the housing. In this condition, the ball 33 establishes a conductingpath between the plug 27 and the housing 26 which are furnished withrespective contacts and conducting wires 36, 37. The roughened walls ofthe housing form a more elastic surface to increase motion of the balland thus sensitivity of the motion detector. As the ball rests upon thepivot 31 in the chamber 32, a slight movement of the instrument causesthe ball to move on the pivot from one wall portion to the other, thusintermittently making and breaking a conducting path in an electricalcircuit including wires 36 and 37 The apparatus described above,including the motion detector, is also described in a copending US.application of James M. Lindsey, Ser. No. 776,184, filed Nov. th, 1968,now Pat. No. 3,546,478.

Referring now to FIG. 2 of the drawings, a circuit is shown forutilizing signals from the motion-sensing device described above foroperating in a borehole instrument. The circuit includes a motiondetector 41 such as the one described above, which provides a signalindicative of motion of the tool to a motion detector amplifier 42. Themotion detector amplifier feeds the signal from the detector to a resettrigger 43 which in turn sends a pulse over a reset line 44 to a countercircuit 46. The reset trigger 43 is a transistor switching circuit whichoperates in response to signals from the motion detector amplifier. Thereset trigger output is normally at zero-voltage level, but uponreceiving trigger signals from the motion detector amplifier 42, theoutput of the reset trigger changes to a high level, which resets thecounter 46 to zero. The counter 46 is comprised of a series of ACflip-flops 47 arranged in a ripple count configuration. At time basecircuit 48 which is comprised of a low-frequency, unijunction oscillatorprovides a continuous output of positive going pulses to the ripplecounter.

The output signal of the ripple counter is fed to a lamp drive amplifier49, which in turn provides the necessary power to lamps 18 (FIG. 1) orother device to be operated within the borehole tool. When the lampdrive amplifier ceases to operate, a negative signal is applied to aclamp trigger 52, which is a monostable multivibrator or one-shotproviding a one-pulse output which in turn is fed to a reset clamp 53,whereupon the clamp trigger 52 goes back to zero. The reset clamp 53,however, is similar to a flip-flop and the single positive pulse fromthe clamp trigger 52 activates the reset clamp to provide a continuouspositive output of the reset clamp as long as there is battery voltageon the reset clamp, even though the clamp trigger goes back to zero. Thecontinuous output of the reset clamp is fed to the reset trigger 43. Thereset trigger in turn puts a continuous reset signal of positive voltageon the reset line 44 which keeps the counter 46 set to zero. The countergoes to zero any time a voltage is on the reset line 44, with the outputof the resettrigger 43 being a continuous voltage when the reset clamphas been activated.

On the other hand, when the signal for activating the reset trigger 43is provided by the motion detector amplifier, the reset trigger conductsto form only a positive spike when the motion detector is closed or inother words, when the motion detector is outputting a signal.

In the operation of the circuit described above, the time base 48generates pulses that are fed to the flip-flop counter 46 and counted bythe counting apparatus. At the end of some predetermined period of timewhich, for example,- in the present application for driving lamps in aphotographic process is several seconds, the ripple counter will have anoutput voltage on the last flip-flop. This causes the lamp driveamplifier 49 to turn on the lamps 18 which expose the film disc 16 to aninstrument image. If the motion detector 41 senses motion within thispredetermined period of lamp operation, its signal is amplified and sentto the reset trigger 43, which in turn sends a pulse to the counter 46resetting all the flip-flops 47 to zero. Thus the counter starts itscounting sequence over again in the absence of such signal from themotion detector.

When the lamp drive amplifier 49 is activated by the positive output ofthe ripple counter 46, the lamp drive amplifier will supply power to thelamps. Power is supplied to the lamps for a period equal to the time ittakes to place a positive voltage on the last flip-flop in the series.The last flip-flop in a ripple counter will conduct for such a period,this being the nature of operation of a ripple counter. However, ifmotion is detected by the motion detector 41 during the period that thelamp drive amplifier normally is conducting, such motion detector signalwill be passed through the reset amplifier to the ripplecounter, whichwill set all the flip-flops in the ripple counter to zero and stop'thelamp drive amplifier from conducting for its nonnal period. The circuitmay be designed, if desirable, to provide for continuous operation ofthe lamps for the normal period of the counter, once the lights haveturned on, regardless of motion from the motion detector. 7

When the lamps turn off, whether by operation of the counter or themotion detector, the negative signal from the lamp drive amplifier ispassed to the clamp trigger 52 which sends a pulse to the reset clamp53. The reset clamp provides a continuous output to the reset trigger,which in turn provides a continuous reset voltage to the counter,thereby keeping the counter set to zero. To reset the circuits ordeactivate the reset clamp, the battery voltage must be broken.

In the operation of the borehole tool and circuit just described, thewell tool is provided with power such as by the insertion of batteriesinto the power supply section 11 just prior to inserting the tool intothe well, whereupon motion will be sensed by the motion detector untilthe tool has reached its operating position in the borehole. Whendetecting the motion which would normally be present while the tool isbeing assembled and positioned for running into the wellbore, the motiondetector 41 will cause an output signal from the motion detectoramplifier 42 to the reset trigger 43. The resulting output from thereset trigger 43 is fed to the ripple counter 46,

last flip-flop receives a zero voltage to stop power application to thelamps and also send a negative signal to the clamp trigger 52. This inturn causes the reset trigger to operate continuously to prevent furtherapplication of power to the lamp until the tool is retrieved to thesurface and battery power to the circuit is broken.

While a particular embodiment of the present invention has been shownand described, it is apparent that changes and modifications may be madewithout departing from this invention in its broader aspects, andtherefore, the aim in the appended claims is to cover all such changesand modifications as fall within the true spirit and scope of thisinvention.

What is claimed is:

1. In an apparatus for controlling the operation of a borehole toolfunction: counting means for initiating signals to start and stop anoperation of the borehole tool after a predetermined time lapse from azero time reference; means responsive to a downhole event for resettingsaid counting means to said zero time reference; and means responsive tothe stopping of the operation of said borehole tool for continuouslyoperating said resetting means.

2. The apparatus of claim 1 wherein said counting means is comprised ofa series of flip-flop circuits in ripple count configuration.

3. The apparatus of claim 1 and further including a motion detector fordetermining the downhole event and wherein said resetting means includesa trigger circuit arranged so that said motion detector activates saidtrigger circuit to send a resetting signal to said counting means.

4. The apparatus of claim 1 wherein said means for continuouslyoperating said resetting means includes a clamping circuit responsive tothe cessation of a signal from said counting means for providing acontinuous signal output to said resetting means.

5. The apparatus of claim 4 wherein said clamping circuit includes aone-shot responsive to the cessation of the borehole tool operatingsignal for providing a single output pulse and a solid-state switchwhich is responsive to said single output pulse for providing acontinuous signal to said resetting means.

6. In a downhole surveying instrument having a photographic systemincluding a lamp for photographing an instrument indicative of aborehole parameter, means for initiating and stopping the application ofelectrical power to the lamp, which means comprises: motion-detectingmeans for providing an electrical signal indicative of the absence ofmotion of the instrument; counting means operative over a predeterminedtime period from a zero time reference for providing an output signal tooperate the lamp; means for continuously providing timed output pulsesdirectly to said counting means for operating said counting means;resetting means responsive to the signal from said motion-detectingmeans for setting said counting means to the zero time reference; andclamping means responsive to the cessation of the signal from saidcounting means after the predetermined time period for supplying acontinuous signal to said resetting means.

7. The apparatus of claim 6 wherein said counting means is comprised ofa series of flip-flops in ripple count configuration.

it i i

1. In an apparatus for controlling the operation of a borehole toolfunction: counting means for initiating signals to start and stop anoperation of the borehole tool after a predetermined time lapse from azero time reference; means responsive to a downhole event for resettingsaid counting means to said zero time reference; and means responsive tothe stopping of the operation of said borehole tool for continuouslyoperating said resetting means.
 2. The apparatus of claim 1 wherein saidcounting means is comprised of a series of flip-flop circuits in ripplecount configuration.
 3. The apparatus of claim 1 and further including amotion detector for determining the downhole event and wherein saidresetting means includes a trigger circuit arranged so that said motiondetector activates said trigger circuit to send a resetting signal tosaid counting means.
 4. The apparatus of claim 1 wherein said means forcontinuously operating said resetting means includes a clamping circuitresponsive to the cessation of a signal from said counting means forproviding a continuous signal output to said resetting means.
 5. Theapparatus of claim 4 wherein said clamping circuit includes a one-shotresponsive to the cessation of the borehole tool operating sigNal forproviding a single output pulse and a solid-state switch which isresponsive to said single output pulse for providing a continuous signalto said resetting means.
 6. In a downhole surveying instrument having aphotographic system including a lamp for photographing an instrumentindicative of a borehole parameter, means for initiating and stoppingthe application of electrical power to the lamp, which means comprises:motion-detecting means for providing an electrical signal indicative ofthe absence of motion of the instrument; counting means operative over apredetermined time period from a zero time reference for providing anoutput signal to operate the lamp; means for continuously providingtimed output pulses directly to said counting means for operating saidcounting means; resetting means responsive to the signal from saidmotion-detecting means for setting said counting means to the zero timereference; and clamping means responsive to the cessation of the signalfrom said counting means after the predetermined time period forsupplying a continuous signal to said resetting means.
 7. The apparatusof claim 6 wherein said counting means is comprised of a series offlip-flops in ripple count configuration.